Current Indicator/Transducer
models MFC-300/I-IAC and I-IDC
Technical Manual
Licht
Contents
1
Introduction
2
2
Front panel indication
3
3 Configuration
3.1
Parameter reset
4
4
4 Programmable parameters
4.1
General parameters
4.2
Current outputs (option)
4.3
MODBUS protocol
4.4
DNP3 protocol (option)
4.5
Language
5
5
5
5
6
7
5
Additional versions
8
A
Specifications
9
B
Housing diagrams
10
C
Weatherproof enclosure layout
13
D
Connection diagrams
14
E
MODBUS registers
17
Rev. A1 (18–01–12) MFC-300/I-IAC and I-IDC Technical Manual
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1 Introduction
The MFC-300/I-IAC and I-IDC are precise, highly reliable and versatile microcontrolled
devices designed to read, display and retransmit AC or DC current values. They feature
one isolated RS-485 port, which can be used for communication using the MODBUS or
DNP3 protocols.
Signals that enter and exit the indicator are galvanically isolated, preventing potentially
damaging noise and transients from being transferred between subcircuits or retransmitted
to other devices.
Figure 1.1 MFC-300/I-IAC and MFC-300/I-IDC Indicators
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2 Front panel indication
During operation, the MFC-300/I-IAC and MFC-300/I-IDC alternates between each input’s current indication. The presented value is equal to the measured current multiplied
by the Sampling Factor parameter.
If more than 2 inputs are used, a timer automatically changes the channels on display.
The user may manually alter the currently displayed channel (skipping the alternation
timer) by pressing the ↑ or ↓ keys.
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MULTI FUNCTION CONTROLLER MFC-300/I-IAC
Input 1:
Input 2:
R1
R2
R3
R4
R5
R6
R7
P
3.12 A
0.56 A
R8
R9
C
R 10 R 11 R 12 R 13 R 14
Figure 2.1 Front Panel
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3 Configuration
Parameterization
The MFC-300/I-IAC and MFC-300/I-IDC feature 4 keys to access their functions. The
procedure to configure any parameter is as follows:
1. Press the P key to enter the parameters menu.
2. Enter the currently configured 4 letter password one letter at a time, using the ↑
and ↓ keys to select each letter and P to advance between letters. The default
password is AAAA.
3. Using the ↑ and ↓ keys, choose the desired parameter.
4. Press P to confirm the parameter’s selection.
5. Choose the desired value with the ↑ and ↓ keys.
6. Confirm pressing P.
By holding down the ↑ or ↓ keys it is possible to advance through the options faster.
The configuration sequence can be cancelled at any time by pressing C.
3.1 Parameter reset
The MFC-300/I-IAC and MFC-300/I-IDC can be reset to factory settings. This procedure
also resets its password to AAAA. To do so, power up the device while pressing C.
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4 Programmable parameters
The MFC-300/I-IAC and MFC-300/I-IDC were developed to provide the user with the
greatest possible flexiblity, such that all supervision and configuration can be executed
on-site or remotely through the existing communication channels.
We define all user-configurable parameters below.
4.1 General parameters
Parameter: Sampling Factor
Options: 1 to 1000.
Description: ratio between the current displayed by the MFC-300/I-IAC or MFC-300/IIDC and the sampled current.
Parameter: AC frequency
Options: 60 Hz, 50 Hz.
Description: input current frequency (only applicable to the MFC-300/I-IAC).
4.2 Current outputs (option)
Parameter: Output Scale
Options: 0-1, 0-5, 0-10, 0-20, 4-20 mA
Description: refers to the various configurable current loop scales.
Parameter: Full Scale
Options: 0.01 to 10.00 A, in increments of 0.01 A.
Description: input current corresponding to the current loop’s full scale output. For
example, if Full Scale = 5.00 A and Output Scale = 4-20 mA, the current loop output will
be 4 mA for a 0.00 A input and 20 mA for a 5.00 A input.
4.3 MODBUS protocol
Parameter: Baud Rate
Options: 9600, 19200, 38400, 57600, 115200 bps.
Description: baud rate for the RS-485 link.
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Parameter: Format
Options: 8N1, 8E1, 8O1, 8N2.
Description: symbol transmission format, where:
◦ 8N1: 8 data bits, no parity, 1 stop bit.
◦ 8E1: 8 data bits, even parity, 1 stop bit.
◦ 8O1: 8 data bits, odd parity, 1 stop bit.
◦ 8N2: 8 data bits, no parity, 2 stop bits.
Parameter: Address
Options: 1 to 247.
Description: MODBUS address for the MFC-300/I-IAC or MFC-300/I-IDC.
4.4 DNP3 protocol (option)
Parameter: Baud Rate
Options: 9600, 19200, 38400, 57600, 115200 bps.
Description: baud rate for the RS-485 link.
Parameter: Format
Options: 8N1, 8E1, 8O1, 8N2.
Description: symbol transmission format, where:
◦ 8N1: 8 data bits, no parity, 1 stop bit.
◦ 8E1: 8 data bits, even parity, 1 stop bit.
◦ 8O1: 8 data bits, odd parity, 1 stop bit.
◦ 8N2: 8 data bits, no parity, 2 stop bits.
Parameter: Address
Options: 0x0000 to 0xFFEF.
Description: DNP3 outstation address in hexadecimal notation.
Parameter: Application Layer Confirmation
Options: Only when transmitting events or multi-fragment responses, Always.
Description: Selects when the MFC-300 outstation should request application layer
confirmations.
Parameter: Maximum Inter-Octet Gap
Options: 2 to 100 ms.
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Description: The DNP3 specification states that frames should not have inter-octet
gaps. In accordance, the MFC-300 never inserts inter-octet gaps when transmitting data.
However, we allow the option to tolerate gaps in incoming transmissions. Frames featuring
inter-octet gaps larger than the Maximum Inter-Octet Gap will be quietly dropped.
Parameter: Backoff Delay (Fixed)
Options: 1 to 100 ms.
Description: See description for Backoff Delay (Random).
Parameter: Backoff Delay (Random)
Options: 1 to 100 ms.
Description: The MFC-300 is designed for multi-drop scenarios where more than one
outstation may transmit over the same line. To handle collision avoidance, a backoff
scheme is implemented. Before transmitting, the MFC-300 always waits for the line to
become idle. Once that happens, it waits for Tdelay = Tf ixed + Trandom ms, where Tf ixed
is the fixed backoff delay and Trandom is a random value, uniformly distributed between 0
and the random backoff delay parameter. If after Tdelay ms the line is still idle, then the
MFC-300 begins transmission.
Parameter: Insert Inter-frame Gap
Options: Never, Always.
Description: The DNP3 specification states that no inter-frame gaps are required. However, some masters have been observed to drop frames when no inter-frame gaps are provided. This option allows communicating with such non-compliant devices. We discourage
its use, given that the forced inter-frame gap implies a forced backoff-delay.
4.5 Language
Parameter: Language
Options: Portuguese (PT_BR), English (EN_US).
Description: Language of the messages and menus displayed on the MFC-300’s front
panel.
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5 Additional versions
Figure 5.1 MFC-300/I-IAC Indicator (96x96 version)
Figure 5.2 MFC-300/I-IAC Indicator (with weatherproof enclosure)
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A Specifications
Power Supply
Isolated, 80-260 Vac/Vdc.
Power Consumption
8W
Operating Temperature
-10 to 70 ◦ C (LCD display)
-40 to 70 ◦ C (VFD display)
Enclosure Rating
IP20 (96x48 and 96x96 formats)
IP65 (with weatherproof enclosure)
Mounting Options
Panel-mounted
Dimensions
96 x 96 x 190 mm or
96 x 48 x 190 mm
Weight
550 g
DC Input
Scale: specifiable
Error/Non-linearity: 0.2% + 0.1% / 10 ◦ C
AC Input
Scale: specifiable
Error/Non-linearity: 0.5% + 0.1% / 10 ◦ C
Current Output
Scales: 0-1, 0-5, 0-10, 0-20, 4-20 mA
Error/Non-linearity: 0.2% + 0.1% / 10 ◦ C
Galvanic Isolation
(60 Hz, 1 min.)
DC Input
AC Input
Output
Communication
Communication
RS-485 - MODBUS RTU or DNP3
9600, 19200, 38400, 57600, 115200 bps
8N1, 8E1, 8O1, 8N2
Displays
2 lines with 16 characters each (5 mm).
LCD with backlight or VFD.
Relays
10 A @ 250 Vac, 0.5 A @ 125 Vdc
Galvanic Isolation: 2.0 kV, 60 Hz, 1 min.
2.0
2.0
2.0
2.0
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kV
kV
kV
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B Housing diagrams
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C Weatherproof enclosure layout
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D Connection diagrams
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Important considerations
The installation of electronic devices in substations should conform with the recommendations given by recent international standards. The most recent and detailed guide for
installations is IEC 61000-5-2:1997, which was based on decades of laboratory and field
research. We summarize below some of the guidelines contained in IEC 61000-5-2:1997.
For further reading, we recommend the articles and application notes available on our
web site.
a. Shielded cables must be used for connecting potentiometric sensors, current loop
outputs, RS-485 links and the auxiliary supply.
b. Cables must be segregated in trays, ducts or conduits according to their functions.
In particular, power cables must never be routed in the proximity of signal cables,
even if these are shielded. The minimum distances which must be observed are
described in IEC 61000-5-2:1997 and in articles available on-line at this product’s
web page.
c. The electrical continuity of cables, ducts, trays and conduits must be preserved up
to frequencies in the order of MHz, over all their extension, including curves and
junctions. In order to guarantee this continuity, joints and bonds should present
electrical contact along each cable, duct or tray’s transversal section. In particular,
trays should be bonded with seam-welded joints (best), U-brackets with multiple
fixings (ok) and never with wires.
d. Shielded cables should present no gaps in their screens along their lengths. 360◦ bonding should be performed instead.
e. Should there be unshielded sections (for example, near terminal block connections),
these should be short as possible.
f. Trays, ducts and conduits must be electrically continuous, and must be grounded
at both ends. In this configuration, trays, ducts and conduits provide shielding
and also perform as parallel earth conductors.
g. Shielded cables should also have their screens bonded at both ends. It is extremely
important that the tray, duct or conduit which contains each cable is also grounded
at both ends, allowing it to perform as a parallel earth conductor. In the absence
of a parallel earth condutor, the cable screens will be exposed to extremely high
currents which will severely compromise their operation.
h. RS-485 pairs must be terminated at both ends by 120 Ω resistors.
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i. RS-485 devices must be connected in a bus topology. No other network topology
(tree, star, ring, etc.) is acceptable.
j. Dry contact inputs (if applicable) must free of potentials.
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E MODBUS registers
The MFC-300 implements the Read Holding Register (0x03), Write Single Register (0x06)
and Write Multiple Register (0x10) MODBUS RTU functions. A frame referring to any
other function will be answered with an "unsupported function code" exception.
We present below the table of remotely accessible registers.
Holding
Register
Description
Values
201
Sampling Factor
1 to 1000
1
202
AC frequency
0: 60 Hz
1: 50 Hz
1
301
Current Loop - Output Scale
0:
1:
2:
3:
4:
0-1 mA
0-5 mA
0-10 mA
0-20 mA
4-20 mA
1
302
Current Loop - Full Scale
0.01 to 10.00 A
100
501
Measured Current
0.000 to 10.000 A
1000
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Multiplier
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